1. Field of the Invention
The invention relates to a signal processing system comprising a source apparatus coupled to a destination apparatus, the source apparatus being arranged for supplying the destination apparatus with a sequence of packets, each comprising a time-stamp, the destination apparatus comprising a clock and being arranged for receiving the packets, for detecting when the time-value of the clock corresponds to the time-stamp in a particular packet, and for thereupon presenting data from that particular packet at an output. The invention also relates to a source and destination apparatus for such a system.
2. Description of the Related Art
Such a system is known for example from the ISO/IEC 11172-1 standard, "Information technology-coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbit/s, Part 1: Systems", first edition 1993-08-01, which will be referred to as the MPEG standard. The systems described by it will be referred to as MPEG systems; these contain for example, an MPEG encoder as source apparatus and an MPEG decoder as destination apparatus.
To supply MPEG encoded signals in a system with more than two apparatuses, it is desirable to supply the MPEG encoded signals over a bus to which a plurality of apparatuses can have access. Such a bus requires an access protocol, which allows different apparatuses to have access in different time-slots allocated to the respective apparatuses. One or more packets can be supplied during a time-slot, and in principle, the duration of the time-slot can be selected to fit the number of packets that have to be transmitted in it.
To minimize the overhead required for time-slot allocation, it is desirable that the time-slot are periodically repeated, each time with the same duration. In this case, the time slot should have a duration long enough to accommodate all the packets that may arrive in a repetition period of time-slot allocation. However, this may lead to overhead when each period of time-slot allocation does not contain the same, integer number of periods of packet arrival, or when the packets arrive irregularly.
It is an object of the invention to reduce the overhead occurring in supplying signal packets over a bus in fixed length time-slots.